I'm getting pretty much exactly a day on IMR 18650, sometimes less, sometimes more.
charged to 4.2v fresh off the charger and drop to about 4.15 usually.
Thats ego-t atty using maybe 4ml a day.
Not usually an issue s you can check the battery volts before going out to decide whether to change.
I would think the above advice is pretty good with the exception that it should be changed to power as that determines the current drawn from the battery, just using the voltage is not taking the atty resistance into account.
I might try some non IMR's I have and see how they last, I don;t have any 'true' 3000mAh, mine say that on the side but they are closer to 1800mAh in reality.